The 39-year-old, who hoisted himself into a share for fifth in the BMW PGA Championship with a closing 66, was up among the frontrunners again in Malmo as he fired a five-under 67 to sit a shot behind the joint leaders Jens Dantorp and Eddie Pepperell.
Starting on the 10th, Gallacher was level-par coming towards the end of his outward half but he moved up the gears with a brace of birdies at the 17th and 18th before picking up three more strokes at the first, third and fourth to power up the order.
Craig Lee birdied his final two holes in a 68 while Scott Jamieson opened with a 69. Chris Doak continued his good recent form with a steady 70 but Marc Warren, who won this event in its previous incarnation as the Scandinavian Masters back in 2006, had to settle for a 74.
Dantorp made full use of home advantage as he took a share of the lead. With most eyes on fellow Swede and world No.2 Henrik Stenson - playing the event for the first time since 2011 - Dantorp, a Malmo native, fired a bogey-free 66 to share the lead with the Englishman Pepperell.
"This is my home course so I try to play it as much as I can when I'm home," said Dantorp. "The support today was great. All my friends, all my buddies were here and there was so much applause. That was one of the biggest keys to my success today. Peter Hanson has helped me a lot. It's great to go to the States to see him over the winter when you can't practise here. He's been a great mentor to me and has helped me through things, so I feel more comfortable in situations such as this."
Dantorp began his round on the back nine and birdied 11 and 12 before picking up further shots on 16 and 18 to reach the turn in 32. More birdies followed on one and six to put the 25-year-old at the top of the leaderboard alongside Pepperell who birdied his final two holes to complete a 66 containing a single dropped shot.
The leading duo were one shot clear of a chasing pack of five players on five under, including two more Swedes in Sebastian Soderberg and Rikard Karlberg, as well as Gallacher, Northern Ireland's Gareth Maybin and the Dutchman Daan Huizing. Spain's Jorge Campillo was a further shot back after a double bogey on his final hole meant that he dropped out of a share of the lead. Lee was joined on four under by the English duo Adam Gee and Paul Waring, another Swede Johan Carlsson and Spaniard Rafa Cabrera-Bello.
Stenson sat three shots behind following an opening 69 to leave him alongside the Spanish veteran Miguel Angel Jimenez whose recent good form has catapulted him to the brink of Ryder Cup qualification at the age of 50. Stenson's erratic 69 contained just seven pars as he began his campaign to avenge a painful play-off defeat by Mark Hensby in 2005.